Washington, April 13 : Researchers and coastal managers detected a bloom of harmful marine algae in the Gulf of Mexico using an underwater microscope, which helped to prevent human consumption of tainted shellfish.
Developed by researchers at the Woods Hole Oceanographic Institution (WHOI) in the US, the instrument is an automated, underwater cell analyzer.
Working with Rob Olson and Heidi Sosik-plankton biologists and instrument developers at WHOI-biological oceanographer Lisa Campbell of Texas A and M University, used their "Imaging FlowCytobot" instrument to detect a substantial increase in the abundance of the algae Dinophysis acuminata in the waters of Port Aransas, Texas.
Dinophysis acuminata produces okadaic acid, a toxin that accumulates in shellfish tissues and can cause diarrhetic shellfish poisoning (DSP) in humans.
DSP is not life-threatening, but symptoms include nausea, cramping, vomiting, and diarrhea.
In mid-February 2008, Campbell reviewed plankton images collected by the Imaging FlowCytobot and detected a substantial increase in the abundance of the dinoflagellate Dinophysis, which occurs naturally in ocean waters worldwide but not usually in harmful quantities.
"We have never before observed a bloom of Dinophysis acuminata at such levels in the Gulf of Mexico," said Campbell.
After reporting the increase to fellow researchers in coastal Texas, Campbell and colleagues collected water samples to confirm that algal toxins were present in the water.
According to Olson, "It is very satisfying to find that a technology we developed as a research tool can be so effective for protecting human health."
"We designed the Imaging FlowCytobot for continuous monitoring of a wide range of plankton, and that turns out to be just what was needed to detect a harmful algal bloom that no one expected," he added.
The bloom and subsequent warning occurred just days before the Fulton Oysterfest, a major shellfish festival in the region. At last report, no shellfish-related human illnesses have been reported in Texas this spring.
"This is exactly what an early warning system should be. It should detect a bloom before people get sick," said Campbell. "So often, we don't figure out that there is a bloom until people are ill, which is too late. The Imaging FlowCytobot has proven itself effective for providing an early warning," he added.
"With time, we have come to see that the instrument has obvious practical uses. It now appears ready to make the transition from basic research tool to operative tool," said Sosik.